That is pretty good with what happens here in my neck of the woods--Zacatecas--with a couple of refinements:

Buenos días ends at 12:00 Noon exactly. Not one minute after. And día is masculine not feminine, so Buenos.

Buenas tardes here does not end at sunset but continues until it is actually dark. Then Buenas noches as a greeting applies. Of course Buenas noches as a good bye (our Good night) also applies. Zacatecans do not seem to have a period of "evening", after sunset and before dark, as do we in the USA.

The problem with students here is that they will tell you Good night in English when greeting you, since they use Buenas Noches as a saludo--greeting. It is hard to get them to remember that "Good night" for us is a despedido--goodbye (something said only when leaving).

One other comment about customs. Here in Zacatecas when two people meet each other on the street and do NOT wish to stop and talk they simply say Adiós and pass on where we estadounidenses would say Buenos Días or Buenas Tardes. Have you noticed that there where you are? But all my neighbors greet me with Buenos Días or Buenas Tardes because they know it is my habit. These Mexicans are sharp!

Re: [jerezano] Evening vs. atardecer

In various parts of Mexico, I have encountered "bueno" (or perhaps it is "buenas/os), without the time period of dias/tardes/noches, particularly when the time is in the blurry part between the divisions of dia/tarde and tarde/noche.

Re: [NinaNina] Evening vs. atardecer

Yes, people in a hurry will often reply bueno or buena and that is it.

Bueno or buen for buen día for the morning and buena or buena tarde for the afternoon. Sometimes only buen if they are really in a hurry to get to work. In Mexico?

Here they are saying good morning or good afternoon for the one day instead of the literal translations: buenos días good morning(s), buenas tardes good afternoon(s) which mean: May all your mornings or all your afternoons or evenings be good. Que tenga(n(s) Ud(s)., tú buenos días, etc.,....